238 
Psyche 
[September-December 
corpora lutea in the bases of their ovarioles. The numbers of work- 
ers manifesting different degrees of fertility are shown in Table II 
for a selection of 25 typical colonies. 
An examination of Table II reveals two facts which are especially 
noteworthy. First, workers with growing oocytes in their ovarioles 
and workers that have actually begun to lay eggs sometimes occur 
in queenright colonies (cf. Colonies 1 and 2 in Table II). One is 
tempted to speculate that these fertile workers are especially likely 
to found “branch colonies.” However, no firm conclusion in this 
regard can be reached. Fertile workers also occur occasionally in 
queenright colonies of H. sublaevis (Buschinger & Winter, 1978) 
and H. canadensis (Buschinger & Alio way, in press), even though 
neither of these latter species appears to produce “branch colonies” 
of the kind seen in H. americanus. Second, some “branch colonies” 
which lacked a fully fertile worker (cf. Colonies 8, 9, 11, and 12 in 
Table II) nevertheless produced Harpagoxenus males, queens, and 
workers. This latter fact, the fact that workers never possess a 
spermatheca, and the fact that most of the “branch colonies” which 
contained fertile workers produced only (cf. Colonies 16, 21, 22, 23, 
24, 25 in Table II) or preferably (cf. Colonies 13, 14, 15, 17, 19, 20 
in Table II) males of the parasite species combine to suggest that 
the queens and workers produced in “branch colonies” may never 
be the offspring of egg-laying workers. Thus, instead of assuming 
that H. americanus workers possess the highly unusual ability to 
produce female offspring parthenogenically (an assumption made 
by Wesson, 1939), we speculate that all workers and queens pro- 
duced in branch colonies may be derived from female larvae which 
are carried over to the “branch colony” nest at the time of its 
initial occupation by H. americanus workers. In this connection, 
we stress that our data regarding the frequency of production of 
males, queens, and workers in branch colonies agree closely with 
those of Wesson (1939). 
Discussion 
The main result of the present study is our failure to confirm the 
assumption (Sturtevant, 1927; Creighton, 1950) that H. americanus 
produces true ergatoid queens (workerlike individuals which pos- 
sess a spermatheca, can be inseminated, and thus can lay fertilized 
eggs and function as colony queens). We suspect that the organ 
